i hear one of my males do the same thing, about 5am in the morning. sounds like a male, try maybe checking the vent area, i went to my parents house the other day and was trying to figure out while none of the quails bonk each other, like the 2 males i have at home keep doing there thing. also wonder why none of my parents eggs would hatch, noticed all 4 where females. i checked the vent area of my males and its swollen and red, but the females are like a bluey colour, you should still get eggs if there are no males, they wont be fertile.
im still trying to work out the sex of my 4-5week old quails, i can hear some calling out, but cant find them when it happens, i need to wait 2 more weeks, also some i can tell by the colour of the front chest area.
maybe if you think one is a male, put him in a cage by himself and see if he calls out. put him where he can see the females but cant get to them,
i had one male try get out of cage, when i put my hand to get eggs the other night, cause he could see a female by herself having some rest as she has lost some feather from her head. he was so determined to get to her, funny thing is he is already with 4 females.